Dave,I think that a VW TDI would be a bit small for a CJ... great motors no doubt, but just a little short on displacement and power for a loaded Jeep.
While power needs and requirements vary person to person I don't know that I would sell the VW motor out due to displacment alone.Compared to a 4.0 Jeep motor (best engine Jeep ever used IMHO) which is roughly 180hp and 210ftlbs (not exact just off the top of my balding head) I looked at the numbers on HPA's site.
100hp and 180ft-lbs stock. Not gonna shatter the planet but at around 40mpg or better I could learn to go slower. And...
A few simple mods and tuning can net in the ball park of 165hp and 280ft-lbs. With proper gearing and some common sense I would have to call those numbers acceptable for anything short of a mud racer, or 4 door JK with a full family and pulling a trailer. But for my expo and wheeling I could easily live with that. And then to be able to wheel all weekend on one tank of Biodiesel? Sold. I'll take two please.:sombrero: